package org.javaqq.face.util;

import java.text.*;

/**
 * Acknowledgment: This file was originally provided by the Ignite Realtime
 * community, and was part of the Spark project (distributed under the terms of
 * the LGPL).
 * 
 * A formatter for formatting byte sizes. For example, formatting 12345 byes
 * results in "12.1 K" and 1234567 results in "1.18 MB".
 *
 * @author Bill Lynch
 */
public class ByteFormat
    extends Format
{
    private static final long serialVersionUID = 0;

    public ByteFormat()
    {}

    // Implemented from the Format class
    /**
     * Formats a long which represent a number of bytes.
     */
    public String format(long bytes)
    {
        return super.format(bytes);
    }

    /**
     * Formats a long which represent a number of kilobytes.
     *
     * @param kilobytes Long kbytes to format as a string.
     * @return String representation of kbytes.
     */
    public String formatKB(long kilobytes)
    {
        return super.format(kilobytes * 1024);
    }

    /**
     * Format the given object (must be a Long).
     *
     * @param obj assumed to be the number of bytes as a Long.
     * @param buf the StringBuffer to append to.
     * @param pos field position.
     * @return A formatted string representing the given bytes in more
     * human-readable form.
     */
    public StringBuffer format(Object obj, StringBuffer buf, FieldPosition pos)
    {
        if (obj instanceof Long)
        {
            long numBytes = (Long) obj;
            if (numBytes < 1024)
            {
                DecimalFormat formatter = new DecimalFormat("#,##0");
                buf.append(formatter.format((double)numBytes)).append(" bytes");
            }
            else if (numBytes < 1024 * 1024)
            {
                DecimalFormat formatter = new DecimalFormat("#,##0.0");
                buf.append(
                    formatter.format((double)numBytes / 1024.0)).append(" K");
            }
            else if (numBytes < 1024 * 1024 * 1024)
            {
                DecimalFormat formatter = new DecimalFormat("#,##0.0");
                buf.append(
                    formatter.format((double)numBytes / (1024.0 * 1024.0)))
                        .append(" MB");
            }
            else
            {
                DecimalFormat formatter = new DecimalFormat("#,##0.0");
                buf.append(
                    formatter.format(
                        (double)numBytes / (1024.0 * 1024.0 * 1024.0)))
                            .append(" GB");
            }
        }
        return buf;
    }

    /**
     * In this implementation, returns null always.
     *
     * @param source Source string to parse.
     * @param pos Position to parse from.
     * @return returns null in this implementation.
     */
    public Object parseObject(String source, ParsePosition pos)
    {
        return null;
    }
}
